Components which are used in corrosive surroundings or hot surroundings often have layers which improve the corrosion protection or only allow use at higher temperatures. This applies, for example, to components of turbines in aircraft or turbines for the stationary generation of current. The turbine blades, but also combustion chamber elements, have a metallic protective layer for corrosion and/or oxidation protection and, in especially hot regions, a ceramic heat insulation layer.
Depending on the component geometry, which changes as a result of the design, or another coating materials or coating methods, the coating parameters have to be checked and optimized.
This may, of course, take place in that an entire component is coated and the adhesion of the layers to the substrate of the component and the adhesion of the layers to one another are investigated by the component being destroyed, that is to say being cut through completely, and by the cut surfaces being investigated by metallography. This, however, leads to the total loss of the component.
It is also known to solder, adhere or weld coupons or wafers onto the surface of the component and to check the coating parameters.